1. Field of the Invention
The present invention relates to a lifting device and, more particularly, to a lifting device for lifting and lowering the backrest of a chair so as to adjust the height of the backrest.
2. Description of the Related Art
A conventional chair comprises a support base, a seat mounted on the support base, a substantially L-shaped backrest support mounted on the support base, and a backrest mounted on the backrest support and located above the seat. The backrest support can be pivoted relative to the support base to move the backrest so as to adjust the inclined angle of the backrest relative to the seat. However, the backrest has a fixed height so that the height of the backrest cannot be adjusted according to a user's requirement, thereby easily causing an uncomfortable sensation to the user.